People frequently find it necessary measure distances. One area in particular where distance measurements are required is in the construction business. One specific example of a construction activity that requires measuring distances is establishing a desired grade for a particular area of land. The “grade” (a.k.a. slope, incline, gradient, pitch or rise) of a physical feature, topographic landform or constructed element, refers to the amount of inclination of that surface to the horizontal plane or reference plane. One special case of gradient occurs where the grade equals zero thereby indicating gravitational level.
For example, when determining if a particular area of ground is level, a leveling pole is frequently used. Most conventional leveling poles comprise an outer liner member and a plurality of inner liner members associated together to form a telescopically adjustable relationship. A scale is provided on a surface of the plurality of members wherein such scale is suitable for measuring distance. The plurality of members is extended as needed and such scale is used to measure the distance of interest.
Consider the activity of preparing a site for the installation of a flat concrete pad. One initial task is to establish one point that represents the final finished surface height (i.e. a “reference point”). Next, using a prior art laser system and leveling pole, a laser emitter is set on a tripod a distance from the reference point and typically outside the area to be leveled. A laser detector is associated with a leveling pole and the leveling pole is positioned at the reference point. The leveling pole is adjusted/extended (thereby causing the laser detector to move) until the detector signals that it has detected the laser light emitted by the laser emitter. Using the measuring marks provided on the leveling pole, the height at the reference point is determined (i.e. the zero point). The height measured at the reference point is the “reference height”. Suppose such reference height is 4 feet 5 inches. Next the leveling pole is moved to a second point of interest and the process repeated and the height of the laser detector relative to the laser emitter at such second point of interest is determined to be 5 feet 7 and ¾ inches. By subtracting the reference height measurement from the height measurement for the second point of interest, the user determines a height delta between the two points. In the above example, the height delta is 1 foot and 2.75 inches (5′7.75″−4′5″=1′2.75″). Such process is repeated as many times as needed to level the area of interest.
As noted above, to determine the difference in height between point two and the reference point, a calculation is required. Such is one drawback of such prior art system as such calculation often requires a calculator or a pencil and paper to perform accurately. Quite often unskilled workers are used who may not be proficient in making such calculations and such workers may make a calculation error resulting in wasted work and lost time. Indeed, even those skilled in making such calculations may make errors. In all cases, time is required to make such calculations (even accurate calculations). Generally speaking, time is money and such is particularly true in the construction business.
Additionally, when moving between different points of interest, it is often necessary to move the laser detector to a different point along the leveling poll and perhaps a different leveling pole member. Such adjustments also take time and provide yet another opportunity to make additional errors.
The present invention eliminates or minimizes all of the above-mentioned drawbacks and disadvantages associated with the use of such prior art system.